This invention relates, generally, to film processor apparatus and, more particularly, to an improved automatic switching system for such devices. This invention is related to the inventions disclosed in copending applications U.S. Ser. No. 07/635,281 filed Dec. 28, 1990, entitled Heat Exchanger, U.S. Ser. No., 07/641,459 filed Jan. 14, 1991, entitled Roller Tank, U.S. Ser. No. 771,737, entitled Improved Solution Filling System For A Film Developer Apparatus, filed Oct. 4, 1991, and U.S. Ser. No. 771,203, entitled Top-Drop Film Feed System, filed Oct. 4, 1991. All of these applications are assigned to the assignee of the present application. The disclosure of these copending and commonly assigned applications are intended to be incorporated by reference herein.
As is known in the art, typical film processors operate in three modes: "off"; "run"; and; "stand-by". In the "off" mode, all operating systems of the processor are off. In the "run" mode, all operating systems of the processor are on. In the "stand-by" mode, all operating systems of the processor are off except, generally those systems associated with maintaining the temperature of the developer solution. Some processors, in addition to maintaining the temperature of the developer solution, also enter into a "jog" cycle during the "stand-by" mode, in which the transport rollers or transport belts go into operation for a short pre-selected time, in order to minimize crystallization of evaporating developer and/or fixer on the rollers or web belts which carry the film through the processor.
In order to process film in a film processor, the processor must be in the "run" mode and the developer solution must be elevated to a pre-selected temperature. Typical film processors are manually switched from the "off" mode to the "run" mode at the start of each day. After the developer solution reaches its pre-selected temperature, the processor is ready and able to automatically process (i.e. develop, fix, wash and dry) film.
When the apparatus is in the "run" mode, with all systems operating, the apparatus consumes electricity and generates substantial heat (from its dryer system). This heat causes evaporation, and degeneration, of the developer and fixer solutions. Additionally, in the "run" mode the gearing, rollers, motor and pumps are gradually worn down through general wear and tear. Accordingly, typical film processors have a "stand-by" mode. As indicated, in the "stand-by" mode, most operating systems are in the "off" mode, to minimize evaporation and wear and tear. Only the developer solution heating system remains in operation, to maintain the developer at the proper temperature for immediate use.
Typical film processors employ manual, semi-automatic and automatic means to switch the processors between their "stand-by" and "run" modes. In manual systems, the operator manually presses a switch, causing the processor to switch from "stand-by" to "run" and thereafter, the operator inserts films for automatic processing. After completion of processing, the operator must then manually press a switch to return the apparatus to "stand-by". In semi-automatic systems, the operator manually presses a switch to cause the apparatus to switch from "stand-by" to "run" and thereafter may insert films for processing. Then, after a pre-selected time (sufficient for the operator to insert and process a standard quantity of films), the apparatus automatically returns to "stand-by". In automatic systems, the act of inserting films triggers an infra-red switch or delicate manual sensors, for example, which automatically cause the processor to switch from "stand-by" to "run" for a fixed period of time sufficient to allow full processing of the inserted film. After processing, the automatic processor automatically returns to "stand-by".
However, in typical film processor apparatus employing automatic switching systems, the switching systems are somewhat expensive and often difficult to service, and are prone to operational problems due to the corrosive nature of fumes from the developer solutions, which attack the infra-red sensors, the delicate manual sensors, and associated printed circuit boards. In typical film processors employing manual or semi-automatic switching systems, operators frequently forget to press switches when required, resulting in films being left within processors which entered "stand-by" prior to completion of a full processing cycle, or resulting in processors being left in the "run" mode all day long, producing excessive wear and tear and excessive evaporation of solutions.
Thus, an improved switching system for film processor apparatus is desired.
One object of this invention is to provide an improved automatic film processor for developing film.
Another object is to provide a switching system which does not require an operator to remove or activate switches.
Another object is to provide such a processor wherein the switch is not subject to corrosion from film developing chemicals.
Other objects of this invention will be apparent to those skilled in the art in light of the following description and accompanying drawings.